The purpose of this project is to study the effects of environmental pollutants, such as heavy metals, pesticides, and carcinogenic polycyclic hydrocarbons, on the extrahepatic biotransformation of foreign chemicals and intestinal transport of nutrients. The results from this study show that alteration of xenobiotic-metabolizing enzymes in small intestine elicited by exposure to environmental contaminants depends on the type of substrate and animal species used. The intestinal transport of nutrients is generally inhibited in rats exposed to either TCDD or lead salts. BIBLIOGRAPHIC REFERENCES: Chhabra, R.S. and Fouts, J.R.: Biochemical properties of some microsomal xenobiotic-metabolizing enzymes in rabbit small intestine. Drug Metab. Disp. 4: 208-214, 1976. Tredger, J.M. and Chhabra, R.S.: Preservation of various microsomal drug-metabolizing components in tissue preparations from the livers, lungs, and small intestines of rodents. Drug Metab. Disp. 4: 451-459, 1976.